Industrial power clamps are adapted for mounting on a base with a power actuated clamp arm positioned to secure a production workpiece or similar object in an industrial environment. Linkage for actuating the clamp arm, unless enclosed, may be exposed to dust, dirt, abrasive particles, or the like which may cause undue wear and malfunction.
Provisions for covering the linkage have been employed such as disclosed in U.S. Pat. Nos. 4,637,597 and 5,064,177. A more complete sealing against particle intrusion has been accomplished by provision of a pivoted clamp arm actuated by internal linkage completely enclosed in the housing so that only a rotary shaft passing through a protective bushing extends between the completely enclosed linkage and an exposed exterior clamp arm. Such a construction has been commercially available from Tunkers GMBH Ratingan, Germany as disclosed in catalog sheet Model No. PK550K; in German Patent No. 2,555,207; and U.S. Pat. No. 4,905,973.